In-depth insights into the evolution of NiFeCrCu multicomponent alloy in the course of the catalytic growth of carbon nanofibers

Abstract

Multicomponent alloys attract growing attention to be applied in various fields of science and technology. In the present study, Ni₅₂Fe₂₂Cr₁₅Cu₁₁ alloy was produced via a single-stage method of electric explosion of wire. It was shown that this method makes it possible to obtain a phase-pure powder (solid solution with a fcc structure, a = 3.583 Å) consisting of spherical nanoparticles with an average diameter of ∼70 nm. According to chemical analysis data, the formed alloy nanoparticles are close in composition to the target ratio of metals. Depending on the treatment procedures such as reduction in hydrogen, heating in argon, calcination in air, and catalytic chemical vapor deposition of C₂-C₄ hydrocarbons, the alloy undergoes different changes. The evolution of the phase composition and magnetic properties of the alloy was monitored using X-ray diffraction analysis and ferromagnetic resonance spectroscopy. As found, the alloy exhibits the phase stability while treating in argon only. Its treatment in hydrogen at temperatures of 500 °C and above facilitates the damage of the solid solution. During the catalytic chemical vapor deposition process performed at 650 °C for 30 min, the carbon yield reached the value of 42 g/g_cat. According to transmission electron microscopy, the morphology of the deposited carbon is represented by a set of nanofibers with a mosaic structure. The resulting carbon nanofibers have a specific surface area of ∼330 m²/g and a pore volume of ∼0.8 cm³/g.